chromium/third_party/blink/manual_tests/print-before-load.html

<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
<head>
<title>Print Test Page</title>
<body>

<script language="JavaScript" type="text/javascript">
window.print();
</script>

This webpage should pop up a print dialog. If you print from that dialog, you
should see this output on paper.

</body>
</html>